Electrical protective arrangement



Nov. 23 ,1926 4 1,608,146

, A. M. TROGNER ELECTRICAL PROTECTIVE ARRANGEMENT- Filed Fe 1922 2 Sheets-Sheet 1 I nve'ni; or

Arthur M. Troqner Attornev Nov. 23 1926. 1,608,146

A. M. TROGNER' ELECTRICAL PROTECTIVE ARRANGEMENT Filed Feb. 27, 1922 2 5 316 2 Inventor Arthur M. Trog ncr By W At "torney Patented Nov. 23, 1926.

UNITED STATES Parent orries.

ARTHUR M. TROGNER, OF TAKOMA PARK, ddARYLAND, ASSIGNOB TO RADIO,

INC., OF NEW YORK, 11'. Y A COREORATZON 0F DELAWARE.

ELECTRICAL PROTECTIVE AIR-RAN GEMEN T.

Application filed February My inventionrelates generally to a protective device for electrical oscillation generators, and more particularly to vacuum tube generators for radio transmitting systems, and has for an object the provision or a device so constructed that both the load and exciting circuits will be active or inactive together.

Another object of the invention is the provision of a device for automatically disconnecting the plate potential of a vacuum tube generator when the antenna or other load accepting circuit ceases to function, thereby preventing a destructive effect on the elements of the tube.

With the above and other objects in view, the invention consists in the combination, construction, and arrangement of parts as will be hereinafter described.

A vacuum tube oscillator or generator when coupled to a load accepting circuit, such as a radio transmitting antenna, gener ally operates in the neighborhood of etiiciency, which means that 50% ofthe energy supplied to the tube is delivered to the load circuit and 50% is dissipated in the tube and its connections. Now if for any reason the load circuit fails to function and no change is made in the energy supply to the tube, practically all or" the energy must be dissipated in the tube, resulting in a great overload with consequent excessive heating and serious damage to the elements of the tub'e,particularly the anode or plate. My invention provides means for protecting vacuum tubes under circumstances of this kind, and therefore permitting of design to allow use of'suchtubes to full capacity.

Reference is to be had to the accompanying drawings forming part of the specification in which like reference characters inclicate corresponding parts throughout the several views and in which Figure 1 is a perspective view of my invention, partly broken .away to show the interior,

Fig. 2 is a diagrammatic view of the preferred arrangement of circuits used with my device,

Fig. 3 is a diagrammatic View of a modified arrangement of circuits,

Fig. 4 shows the position of the contacts when the device is at rest,

27, 1922. Serial No. 539,745.

Fig. 5 is a similar view when the oscillatory circuit is functioning properly, and

Fig. 6 is a similar view when oscillations in the load circuit fail.

My invention comprises two hot wire elements similar to those used in ordinary ho wire ammeters, so arranged that with both elements heated or both elements cold the circuits controlled thereby are active or inactive together as the case may be. One of the elements is connected with the load circuit and the other element with the exciting or supply circuit or, if desired, with what may be termed the keying circuit. when the key in this latter circuit is closed the current flowing through the exciting circuit heats the element of the protective device connected therewith and, at the same time. the oscillations. generated in turn in the load circuit cause the other element to become heated, keeping the protective device in what might be called neutral state. If, however, for any reason, such as an opening in the load circuit, leaky insulator, or the like, oscillations cease or are not started, the

element connected with the load circuit will become cold, or will not heat, causing a pointer to close auxiliary contacts, short circuiting'a' solenoid of a relay in the keying circuit whereby said circuit will open, stopping energy flow in the exciting circuit, thus protecting the vacuum tube and by the use of suitable apparatus warn the operator of the existing trouble. 7

Referring to Figure 1 of the drawings, A and B indicate two hot wire elements, one of which is connected with the load or oscillatory circuit, indicated in its entirety by C, and the other connected with the exciting circuit, or if desired, with the keying circuit indicated generally by D and E, shown respectively in Figs. 2 and 3. The ends of the elements are secured in posts 8, 9, 10, and 11, the posts 9 and 10 being provided with adjusting devices comprising resilient members 12 adjacent to the posts, and insulated therefrom byblocks 13, and insulated screws 15, passing through the posts and resilient members in such a manner that the tension on the elements A and B may be varied by proper manipulation of these screws. Brackets 16 support shafts 17 and 1.8 "operating in suitable bearings 19 which iii) carry pointers and 21. These pointers are so constructed that they operate over scales 22 which may be calibrated in any desired unit. Tension threads 23 and 24 are connected to the center of the elements A and B respectively, the free ends being connected with contraction springs 25 and 26, which are secured to a common post 27. The tension of the springs 25 and 26 is just suflicient to produce movement in the shafts upon expansion under heating of the elements A and B. Auxiliary contacts 28, which are associated with the hot element A, are open when the system is functioning normally and are arranged on the top of the case 14 at the zero end of one of the scales, and in line with the pointer 20 so that when it swings to that end of the scale upon oscillations failing, the contacts will be closed, while at the zero end of the other scale auxiliary contacts 29, which are inclosed position when the system is functioning nor mally, are controlled by the pointer 21 associated with the element B; These two sets of contacts are connected in series and in series with a branch of the keying circuit E. Suitable binding posts 30 for connection with the various circuits are placed so that easy access may be had to them.

As shown in Fig. 2, I prefer to connect the element 13 in series with the exciting circuit D, which circuit includes a source ofenergy 32 and three-electrode vacuum tube 33, condensers 34 and 35, grid leak 36, relay 37, and inductances 38 and 39. As this circuit and its component parts are of the type usually employed in vacuum tube radio transmitting systems, it is thought that a detailed description thereof would be superfluous. The keying circuit E includes a source of energy 40, relay 41, and key 42, and has a branch with the contacts 28 and 29 in series. The element A is connected in series with the antenna or oscillatory circuit C, which is grounded at 31.

In explaining the operation of my invention, I will not endeavor to describe the action of the circuits during transmission of signals, but will limit myself to the action and results of the protecting device.

hen the key 42 is closed, current flowing through the circuits 40, 41 and 42 causes the energy produced in the solenoid 44 to assert a pull on the armature 37, closing the grid leak circuit 36 which starts oscillations in the. circuits D sustained by energy drawn from source 32 in turn inducing oscillations in the antenna circuit C. Immediately upon current flowing through the circuits D, the element B becomes heated causing the pointer 21, because of expansion in the element B. to be removed from the contacts 29 permitting them to close. The induced oscillations in the antenna cause the element A to heat and through the expansion in this element, the pointer 20 is removed from the contacts 28, permitting them to spring open. If for any reason oscillations should fail to begin when the keying circuit is closed, the element A will remain cold causing no action in the pointer 20, allowing the contacts 28 to remain closed; or if after being started, oscillations stop, the element A becomes cold and through the contraction of this element, the pointer 20 closes the contacts 28. When the system is operating properly, the coil 43 is energized from the battery causing the relay 41 to close the circuit E, but when the coil'43 is short circuited (when both contacts 28 and 29 are closed) short circuiting the battery 40, the spring 45 pulls open the contact of the relay, opening the circuit. In general, the short circuit of battery 40 is of very short duration, but if found in practice to be of a nature as to damage the battery a limiting resistance can be inserted in series with contacts 28 and 29. Although I have not illustrated a means for retarding the action of the keying circuit relay 41 because no particular means are preferable, I find it better to provide such a means, which may be a dash pot or the like, should overlapping action of the pointers 20 and 21 not be embodied in their design. That is, if contacts 29 close before contacts 28 open, coil 43 will be short-circuited, and keying circuit E will be opened preventing'starting operation, so that if action of pointers 20 and 21 is not designed to take care of this, a delayed action of relay 41 shouldbe provided of suflicient duration to permit of starting operation.

Although the circuit shown in Fig. 2 is to be preferred, it is by no means the only arrangement that may be successfully used, as that illustrated in Fig. 3 may be employed equally well. The circuit here shown is similar to that shown in Fig. 2 in so far as its equipment is concerned, but the element B is connected in series with a keying circuit inl stead ofwith the exciting circuit. The operation of starting oscillations and the manner in which the protective device operates should oscillations fail to start, or stopping after having been started, is the same as when the element is connected with the exciting circuit.

In Figs. 4, 5 and 6, I have shown more clearly the position of the pointers 20 and 21 and condition of the contacts 28 and 29 during different operations of the device. In Fig. 4, the device is represented as being at rest, that is, no oscillations are being generated. The pointer 20 is closing the contacts 28 while the pointer 21 is bearing against one of the arms of contacts 29, opening them. As these contacts are connected in series, the solenoid of the relay 41 is energized due to not being short-circuited, and the circuit 40, 41 and 42 is ready for closing by key 42 when desired. When the system is functioning properly, the pointers have a moving range of quite some distance, as shown in Fig. 5. Both elements A and B being heated, both pointers are removed from the contacts, which allows the contacts 28 to open and 29 to close, which as in the condition of Fig. 4 closes relay 41 in the keying circuit as described herein, but should oscillations tail in the circuit associated with the pointer 20, the element connected therewith, will become cold allowing the pointer to drop back on the contact 28, closing the circuit as shown in Fig. 6. The element B being still heated, holds the pointers 21 away from the contacts 29, allowing them to remain closed. If both sets of contacts are closed, current is permitted to pass through the circuit E, which short-circuiting the relay coil 43, opens the keying circuit. Since the pointers and 21 have a large range of swing, they will not have time to operate the contacts 28 and 29 in ordinary telegraphic manipulation of the key 42, so that for such manipulation the transmitting system will always be ready to radiate energy.

It is understood that the above description and accompanying drawings disclose only the preferred embodiment of my invention and that various minor changes in details of construction, proportion, and arrangement or" parts may be resorted to within the scope of the appended claims and without sacrificing any of the advantages of my invention.

Having fully described my invention, what I desire to secure by Letters Patent is 1. In a radio apparatus, a plurality of oscillatory circuits, a source of electrical energy adapted to be employed for setting into operation said oscillatory circuits, and means for establishing a preferred circuit for said source of energy and rendering the same inoperative for setting into operation the oscillatory circuits upon one of the oscillatory circuits failing to function.

2. A protected oscillation generator system comprising a vacuum tube and its oscillation producing circuits, a source of energy for oscillations, a load circuit to receive the oscillations, a thermal device in said load circuit, means for interrupting oscillations in the system, said means being adapted to be actuated by said thermal device on failure of the load circuit to accept oscillations, a second thermal device in the oscillationproducing circuits, and means actuated by said second thermal device to render the system ready for operation after oscillations have ceased.

3. In an oscillation generator comprising input and output circuits in coupled relation, means in one of said circuits for interrupting the generation of oscillations, said means including a source of electromotive force in series with an electromagnet with which isoperatively associated said interrupting means, and a device connected in one of the generator circuits for effectively short circuiting the source of electromotive force and said electromagnet.

4. In an oscillation generator comprising input and output circuits in coupled relation, means in one of said circuits for interrupting the generation of oscillations, said means including a source of electromotive force in series with an electromagnet with which is operatively associated said interrupting means, and a device connected in one of the generator circuits for effectively short-circuiting the source of electromotive force and said electromagnet, said device comprising a single member responsive to current passing through the coupled circuits.

ARTHUR M. TROGNER. 

